Vorimore F.,French Agency for Food Environmental and Occupational Health Safety Anses |
Cavanna N.,French Agency for Food Environmental and Occupational Health Safety Anses |
Vicari N.,Instituto Zooprofilattico Sperimentale della Lombardia e dellEmilia Romagna Bruno Ubertini |
Magnino S.,Instituto Zooprofilattico Sperimentale della Lombardia e dellEmilia Romagna Bruno Ubertini |
And 4 more authors.
Journal of Microbiological Methods | Year: 2012
We describe a novel high-resolution melt assay that clearly differentiates Chlamydia abortus live vaccine strain 1B from field C. abortus strains and field wild-type isolates based on previously described single nucleotide polymorphisms. This modern genotyping technique is inexpensive, easy to use, and less time-consuming than PCR-RFLP. © 2012 Elsevier B.V..
PubMed | French Agency for Food Environmental and Occupational Health & Safety Anses, University of Bath and University of Swansea
Type: | Journal: Applied and environmental microbiology | Year: 2017
Campylobacter is among the most common worldwide causes of bacterial gastroenteritis. This organism is part of the commensal microbiota of numerous host species, including livestock, and these animals constitute potential sources of human infection. Molecular typing approaches, especially multi-locus sequence typing (MLST), have been used to attribute the source of human campylobacteriosis by quantifying the relative abundance of alleles, at 7 MLST loci, among isolates from animal reservoirs and human infection, implicating chicken as a major infection source. The increasing availability of bacterial genomes provides data on allelic variation at loci across the genome, providing the potential to improve the discriminatory power of data for source attribution. Here we present a source attribution approach based on the identification of novel epidemiological markers among a reference pan-genome list of 1810 genes identified through gene-by-gene comparison of 884 genomes of C. jejuni isolates from animal reservoirs, the environment and clinical cases. Fifteen loci, involved in metabolic activities, protein modification, signal transduction and stress response, or coding for hypothetical proteins, were selected as host-segregating markers and used to attribute the source of 42 French and 281 UK clinical C. jejuni isolates. Consistent with previous studies of British campylobacteriosis, analyses performed using STRUCTURE software, attributed 56.8% of British clinical cases to chicken, emphasizing the importance of this host reservoir as an infection source in the UK. However, among French clinical isolates, approximately equal proportions of isolates were attributed to chicken and ruminant reservoirs suggesting possible differences in the relative importance of animal host reservoirs and indicating a benefit for further national-scale attribution modelling to account for differences in production, behaviour and food consumption.Accurately quantifying the relative contribution of different host reservoirs to human Campylobacter infection is an ongoing challenge. This study based on the development of a novel source attribution approach, provides the first results of source attribution in Campylobacter jejuni in France. A systematic analysis using gene-by-gene comparison of 884 genomes of C. jejuni isolates, with a pan-genome list of genes, identified 15 novel epidemiological markers for source attribution. The different proportions of French and UK clinical isolates attributed to each host reservoir illustrates a potential role for local/national variations in C. jejuni transmission dynamics.
Chacon J.L.,University of Sao Paulo |
Mizuma M.,University of Sao Paulo |
Vejarano M.P.,University of Sao Paulo |
Toquin D.,French Agency for Food Environmental and Occupational Health Safety Anses |
And 4 more authors.
Avian Diseases | Year: 2011
Avian metapneumovirus (AMPV) causes turkey rhinotracheitis and is associated with swollen head syndrome in chickens, which is usually accompanied by secondary infections that increase mortality. AMPVs circulating in Brazilian vaccinated and nonvaccinated commercial chicken and turkey farms were detected using a universal reverse transcriptase (RT)-PCR assay that can detect the four recognized subtypes of AMPV. The AMPV status of 228 farms with respiratory and reproductive disturbances was investigated. AMPV was detected in broiler, hen, breeder, and turkey farms from six different geographic regions of Brazil. The detected viruses were subtyped using a nested RT-PCR assay and sequence analysis of the G gene. Only subtypes A and B were detected in both vaccinated and nonvaccinated farms. AMPV-A and AMPV-B were detected in 15 and 23 farms, respectively, while both subtypes were simultaneously found in one hen farm. Both vaccine and field viruses were detected in nonvaccinated farms. In five cases, the detected subtype was different than the vaccine subtype. Field subtype B virus was detected mainly during the final years of the survey period. These viruses showed high molecular similarity (more than 96% nucleotide similarity) among themselves and formed a unique phylogenetic group, suggesting that they may have originated from a common strain. These results demonstrate the cocirculation of subtypes A and B in Brazilian commercial farms. © 2011 American Association of Avian Pathologists.
Carpentier B.,French Agency for Food Environmental and Occupational Health Safety ANSES |
Lagendijk E.,French Agency for Food Environmental and Occupational Health Safety ANSES |
Chassaing D.,French Agency for Food Environmental and Occupational Health Safety ANSES |
Rosset P.,French Agency for Food Environmental and Occupational Health Safety ANSES |
And 2 more authors.
Food Control | Year: 2012
Our aim was to determine factors that have an impact on the bacterial load of inner surfaces of food refrigeration equipment to develop recommendations that should be made to consumers. We investigated 23 domestic refrigerators (DRs) and, for comparison, six serve-over counters (SOCs). Several zones were studied for aerobic mesophilic counts (AMC) presumptive Bacillus cereus and coagulase-positive staphylococci. In addition, for each DR sample, we collected data on the condition of the sampled surface and refrigeration practices. In DRs, there was no correlation between AMC and temperature, relative humidity, pH or cleaning frequency. AMC counts in SOCs, which are cleaned and disinfected weekly, were similar to the figures from the less frequently cleaned DRs, but B. cereus and coagulase-positive Staphylococus were less frequently found in SOCs. In DRs, the highest AMC counts were reached when both condensation and food traces were visible, i.e. when growth conditions were met, resulting in a mean of 10 4 CFU/cm 2 against of mean of 32 CFU/cm 2 on clean surfaces and dry surfaces with food traces. Consequently, two recommendations for consumers are (1) to avoid condensation and (2) to clean up food spills as soon as possible. © 2011 Elsevier Ltd.